Andyh Posted September 11, 2023 Share Posted September 11, 2023 Hi all, new to forum, I have a question on A2A heat pumps. We have a fairly well renovated/insulated bungalow, currently heated with a log burner and oil boiler. I'm currently awaiting quotes for an A2A heat pump, probably a 2-way multi-split system to heat the living areas (effectively front/back of house). Current thinking is for 2 wall mounted units, these would cause the least disruption to the present house layout, however one unit could be floor standing without too much inconvenience. My question is, is there a benefit on floor standing over wall mounted internal units? The floor mounted are more expensive, but logic seems to tell me that a heat source low down should be a better solution (installer says no!). 2nd question, I have a fairly good idea on what I think the heat loss of the 2 spaces is. I wont be surprised if the quotes I receive will be over spec'd, what's the general feeling on this? Is it better to err on the side of caution and put in slightly more powerful units than might be needed or is this wasting money and likely to make the system less efficient? Link to comment Share on other sites More sharing options...
Gone West Posted September 11, 2023 Share Posted September 11, 2023 @Andyh Welcome to the forum. I shall be watching this thread carefully as these are questions I would find the answers interesting to know, as I am considering changing from oil to A2A. Link to comment Share on other sites More sharing options...
SteamyTea Posted September 11, 2023 Share Posted September 11, 2023 Welcome There does not seem to be that much general information about A2AHPs, a few on here have them and rate them highly. The main think about wall mounted, is about noise transmitting though the wall. The other thing is any planning restraints i.e. it is ok to have one, but not two, not at the front of the building. I do wonder why, for self install, one cannot get an ordinary monoblock ASHP, then just plumb it is to fan assisted radiators. I bet the drop in efficiency is not that bad. No messing about with F-Gas, flanging tools, vacuum pump that way, and ordinary plumbing fixtures and fittings. Link to comment Share on other sites More sharing options...
HughF Posted September 11, 2023 Share Posted September 11, 2023 1 hour ago, SteamyTea said: Welcome There does not seem to be that much general information about A2AHPs, a few on here have them and rate them highly. The main think about wall mounted, is about noise transmitting though the wall. The other thing is any planning restraints i.e. it is ok to have one, but not two, not at the front of the building. I do wonder why, for self install, one cannot get an ordinary monoblock ASHP, then just plumb it is to fan assisted radiators. I bet the drop in efficiency is not that bad. No messing about with F-Gas, flanging tools, vacuum pump that way, and ordinary plumbing fixtures and fittings. Interesting, having worked on both types of systems (I class myself as skilled in all things mechanical/pipework related) , give me 1/4" and 3/8" inch lines, a vac pump and some refrigerant over water any day of the week. It's so much easier to thread around the place. Regarding the hi/low mounting, low for heat, hi for cooling... Link to comment Share on other sites More sharing options...
markocosic Posted September 11, 2023 Share Posted September 11, 2023 1 hour ago, SteamyTea said: No messing about with F-Gas, flanging tools, vacuum pump Why? Piece of absolute pish compared with water plumbing... Link to comment Share on other sites More sharing options...
HughF Posted September 11, 2023 Share Posted September 11, 2023 9 minutes ago, markocosic said: Why? Piece of absolute pish compared with water plumbing... Exactly, it’s 100 times easier. And it always works…. None of this ‘no circulation to the last radiator on the circuit’ rubbish…. Link to comment Share on other sites More sharing options...
SteamyTea Posted September 11, 2023 Share Posted September 11, 2023 At the moment you do need your F-Gas though. Link to comment Share on other sites More sharing options...
HughF Posted September 11, 2023 Share Posted September 11, 2023 2 minutes ago, SteamyTea said: At the moment you do need your F-Gas though. Not for r290 you don't... but you knew that... And yes, there are no r290 multi-splits on the market, I knew that... Link to comment Share on other sites More sharing options...
DanDee Posted September 11, 2023 Share Posted September 11, 2023 4 minutes ago, SteamyTea said: At the moment you do need your F-Gas though. Water or f-gas, 90% of customers will still have to pay some qualified professional to do the work, the A/W has it's fair share of professionals getting it wrong. Link to comment Share on other sites More sharing options...
HughF Posted September 11, 2023 Share Posted September 11, 2023 30 minutes ago, DanDee said: Water or f-gas, 90% of customers will still have to pay some qualified professional to do the work, the A/W has it's fair share of professionals getting it wrong. Isn't that the truth... Commercial aircon installers seem to be much more capable... Link to comment Share on other sites More sharing options...
SteamyTea Posted September 11, 2023 Share Posted September 11, 2023 41 minutes ago, DanDee said: the A/W has it's fair share of professionals getting it wrong. 10 minutes ago, HughF said: Isn't that the truth... Commercial aircon installers seem to be much more capable... That is a very good point. I wonder if there is a standard was to calculate the size of A/C units. Just a case of changing the sign to make it heating (near enough). Link to comment Share on other sites More sharing options...
markocosic Posted September 11, 2023 Share Posted September 11, 2023 Eurovent certification? (to convert box kW into actual kW at your design condition) Link to comment Share on other sites More sharing options...
HughF Posted September 11, 2023 Share Posted September 11, 2023 5 minutes ago, SteamyTea said: That is a very good point. I wonder if there is a standard was to calculate the size of A/C units. Just a case of changing the sign to make it heating (near enough). I'll ask my mate... daikin specifying m&e project manager on the embassy gig... Link to comment Share on other sites More sharing options...
Crofter Posted September 11, 2023 Share Posted September 11, 2023 2 hours ago, HughF said: Regarding the hi/low mounting, low for heat, hi for cooling... That makes sense. But most of the units I've seen on the market area designed for high level mounting. Any suggestions for a ducted system which could live under the floor. Is that a good idea? Would make condensate drainage nice and simple. Link to comment Share on other sites More sharing options...
Andyh Posted September 11, 2023 Author Share Posted September 11, 2023 4 hours ago, SteamyTea said: I do wonder why, for self install, one cannot get an ordinary monoblock ASHP, then just plumb it is to fan assisted radiators. I bet the drop in efficiency is not that bad. No messing about with F-Gas, flanging tools, vacuum pump that way, and ordinary plumbing fixtures and fittings. I did look at these, but they seemed to require a couple of humungous holes cut in the wall which put me off Link to comment Share on other sites More sharing options...
DanDee Posted September 11, 2023 Share Posted September 11, 2023 5 minutes ago, Andyh said: I did look at these, but they seemed to require a couple of humungous holes cut in the wall which put me off this? Link to comment Share on other sites More sharing options...
Andyh Posted September 11, 2023 Author Share Posted September 11, 2023 1 hour ago, SteamyTea said: I wonder if there is a standard was to calculate the size of A/C units. Just a case of changing the sign to make it heating (near enough). I got the feeling the chap I was talking to (at least for the heating sizing) took the room area and multiplied by a factor that depended on on how well I said the room was insulated. I think he had 3 values ranging from poor to very good. I suspect the units are twice what I need, but my calculations could be wrong so I wouldn't like to be too confident on that. Also I suspect a fuller survey will be done if I move forward. Link to comment Share on other sites More sharing options...
DanDee Posted September 11, 2023 Share Posted September 11, 2023 17 minutes ago, Crofter said: Any suggestions for a ducted system which could live under the floor. Is that a good idea? Would make condensate drainage nice and simple. A ducted system can go anywhere(ceiling/wall/floor). What is the issue with the ducted system under the floor? Solve that issue and get on with it. Link to comment Share on other sites More sharing options...
Crofter Posted September 11, 2023 Share Posted September 11, 2023 11 minutes ago, DanDee said: A ducted system can go anywhere(ceiling/wall/floor). What is the issue with the ducted system under the floor? Solve that issue and get on with it. No issue that I'm aware of, I've just more often heard about ducted units going on the loft space. Link to comment Share on other sites More sharing options...
DanDee Posted September 11, 2023 Share Posted September 11, 2023 (edited) 19 minutes ago, Andyh said: I got the feeling the chap I was talking to (at least for the heating sizing) took the room area and multiplied by a factor that depended on on how well I said the room was insulated. I think he had 3 values ranging from poor to very good. I suspect the units are twice what I need, but my calculations could be wrong so I wouldn't like to be too confident on that. Also I suspect a fuller survey will be done if I move forward. The AC chaps are used to size the units based on the cooling load need to the measurement of the space, regardless of the level of insulation. Hopefully you can find a company that understands your main concern is heating, and they do a proper heat loss calculation(you can learn to do it yourself) so they can size according to that together with specification of the unit for heating(not cooling). Wall vs floor, in a single room It wouldn't make much difference(except if there's no space for the floor unit to be blocked by a table or couch). When you are trying to heat a larger area that is divided by walls with 2 units like in your case, I would opt for the wall units as they are able to direct/throw the flow of air a bit further into the room, but keep in mind ideally you would have another way to help the heated air migrate(a fan/duct to push or bring air in between the spaces). As the air around the unit heat up, it reduces the output/efficiency and stops whilst the air in the middle is at lower temp. In a water system, the heat is pumped around, with a split air system, you hope for the heat to evenly warm everything around(so plan to act on that) Ideally a central unit with ducts in the attic toward the extremities. watch this random example Edited September 11, 2023 by DanDee 1 Link to comment Share on other sites More sharing options...
magnayn Posted September 11, 2023 Share Posted September 11, 2023 17 minutes ago, DanDee said: watch this random example I had to laugh because I've watched the video he has in the background on the TV - and it's *extremely apparent* at one point where his concerns lie - that A2A is so simple, anyone might be able to do it 😱 No complicated re-plumbing to larger pipework, no worrying about flow temperatures and emitter sizes, no buffer tanks - simple and no need for the grifters. 👍 Link to comment Share on other sites More sharing options...
HughF Posted September 11, 2023 Share Posted September 11, 2023 (edited) It’s almost as if the aircon companies took something that was so genius and simple (air-air, vrf/vrv) then were tasked with making something work by some Europeans who wanted to keep their radiators…. stupid radiator loving people that we are. £2k on pipe and radiators for my install…. £2k that could have gone on another cruise. Ah well, the wife wanted radiators… Although, it does decouple the heat generator from the emitter, and that’s a good thing. Rads and pipework should see out two monobloc units, if you keep on top of the water treatment. Edited September 11, 2023 by HughF Link to comment Share on other sites More sharing options...
magnayn Posted September 11, 2023 Share Posted September 11, 2023 Curious that his Energy efficiency label seems to relate to a very different wall unit.. Link to comment Share on other sites More sharing options...
Beelbeebub Posted September 11, 2023 Share Posted September 11, 2023 29 minutes ago, HughF said: It’s almost as if the aircon companies took something that was so genius and simple (air-air, vrf/vrv) then were tasked with making something work by some Europeans who wanted to keep their radiators…. stupid radiator loving people that we are. £2k on pipe and radiators for my install…. £2k that could have gone on another cruise. Ah well, the wife wanted radiators… Although, it does decouple the heat generator from the emitter, and that’s a good thing. Rads and pipework should see out two monobloc units, if you keep on top of the water treatment. The decoupling thing is the one bit that attracts me to a2w. Radiators, pipes etc are commodity items. More or less interchangeable from a wide variety of manufacturers and suppliers. You dint need to fit vaillant radiators because you have a vaillant boiler. Or Baxi radiators if you have a baxi boiler. Even if you have some weird old boiler that nobody makes any more, you can fit a rad to it. If a2a units were the same that woukd be a big plus. Also, a2a units seem to usually use a separate flow return pair to each emitter. Making it so you can run a flow and return pair around and locally branch off for each emmiter, like we do with rads, would be a big improvement. If they could do that then moving the country to HPs would be a case if fitting a2a systems "in parallel" with the exisiting gas system. That would be there for DHW and for peace of mind about "what if my heatpump can't keep me warm in winter". After a few seasons where people realise they never use the gas boiler they'll be ready to switch fully Link to comment Share on other sites More sharing options...
DanDee Posted September 11, 2023 Share Posted September 11, 2023 47 minutes ago, magnayn said: I had to laugh because I've watched the video he has in the background on the TV Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now